Be Aware of What Lurks in the Night

by Dean Chamberlain
Reprinted with permission from FAA Aviation News

Each
year,
FAA Aviation News looks at some aspect of winter-related
flight operations as a way to remind pilots and maintenance
technicians of some of the risks associated with this time of the
year. In the past, we have discussed such topics as winter survival to
preparing your aircraft for cold weather operations. This year, we are
printing fatal accident data provided by Joe Mooney. Mooney, who works
in the FAA's Office of Accident Investigation, did computer analyses
of almost 30,000 NTSB records from the period 1995-2002. He based his
search upon the listed probable causes. As he said, 'One accident can
have more than one airplane involved, and one airplane can have more
than one probable cause. So we are counting probable causes.'

Mooney provided
data on accidents listing both light and dark probable causes. Then he
compared them to see if 'dark' had any impact on the numbers. For the
purpose of this report, dark includes dusk and night periods. Light
includes day and dawn data. Accident data from Alaska and Hawaii are
excluded. The data are pilot related. Someone had to be flying the
aircraft or involved in the reported accident.

In the following
data, the 'Difference Factor' column is calculated by dividing the
dark accident percentage by the light accident percentage. The number
is an indication of the apparent increased risk factor for dark
operations involving that particular phase of flight.

As you can see,
some 'Difference' factors are very minor. Some are more significant.
Refueling, for instance, is nine times more likely to be a probable
cause during dark than during light conditions. Because this is not a
completely scientific study, we are only providing data to stimulate
thought. But, based upon the following information, the fatal
'Difference Factor' numbers seem to show that phases of flight dealing
with night landings, particularly those involving instrument flight
procedures are more dangerous at night.

Based upon
common wisdom, the following flight profile may explain why the
numbers show that phases of night landings, particularly IFR landings,
have a higher fatal probable cause rating. If you see yourself in this
profile, you may want to reconsider how you fly or when you fly. You
have worked all day. You have flown your own aircraft or your
company's aircraft on a business trip that started before sunrise. You
preflighted in the dark with cold outside air temperatures. You flew
several hours to your meeting. You missed lunch and ate dinner out of
the candy machine. After preflighting for your return trip in the
dark, you are glad to get airborne. You spend another couple of hours
airborne. You are tired and sleepy. As you prepare to fly the
published instrument approach, you realize that instead of being alert
and prepared to fly the procedure, you can hardly stay awake, let
alone remain alert. If there is any type of wind or weather, you have
just increased your risk of making a dumb mistake. Fatigue is a
killer. Are you alert enough to make a safe landing? If you have ever
found yourself in this situation, maybe the next time you see yourself
in this accident profile, you might consider renting a hotel or motel
room and spending the night. Based upon Mooney's work, you can reduce
your odds of dying by several factors by waiting and departing during
the daylight hours the next day. Or, if you don't want to spend the
night, you could take another pilot along with you who could fly the
return leg of your trip. You just need to make sure the pilot gets to
rest or gets some sleep before the return trip. What you don't need is
two very tired and sleepy pilots shooting an approach. You might even
take an air carrier flight and leave the flying to them. Have a safe
holiday period. Hope to see you next spring.